gunpowder consists of from 70 to 80 per cent of niter, with 10 to 15 per cent of each of the other ingredients. Its explosive energy is due to the fact that it contains the necessary amount of oxygen for its own combustion, and liberates gases (chiefly nitrogen and carbon dioxide), which occupy a thousand or fifteen hundred times more space than the powder which generated them. Gunpowder pile driver, a pile driver, the hammer of which is thrown up by the explosion of gunpowder. Gunpowder plot, a plot to destroy the king, lords, and Commons, in revenge for the penal laws against Catholics. As Guy Fawkes, the agent of the conspirators, was about to fire the mine, which was placed under the house of lords, he was seized, Nov. 5. Hence, Nov. 5 is known in England as Guy Fawkes day. Gunpowder tea, a species of fine green tea, each leaf of which is rolled into a small ball or pellet.